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  <title>GoJS Making SVG -- Northwoods Software</title>
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<h1>Making SVG</h1>
<p>
<b>GoJS</b> has one function for creating SVG: <a>Diagram.makeSvg</a>, which returns a new SVGElement with a representation of a GoJS Diagram. The method has a single argument, a JavaScript Object that contains several definable properties, enumerated in the documentation.
</p>
<p>
  SVG export can be useful as content for a PDF.
  Most GoJS users who create PDFs do so by exporting Diagrams to SVG or images and place that content in their PDFs, on the server or elsewhere.
</p>
<p>
  This page is almost identical to the page on <a href="makingImages.html">Making Images</a>, which shows how to render PNG images instead of SVG elements.
</p>
<p>
Below are several examples of using <a>Diagram.makeSvg</a> on the following diagram:
</p>
<!-- Don't bother showing this source -->
<pre class="lang-js" id="diag" style="display: none;">
  // define a simple Node template (but use the default Link template)
  diagram.nodeTemplate =
    $(go.Node, "Auto",
      $(go.Shape, "RoundedRectangle",
        // Shape.fill is bound to Node.data.color
        new go.Binding("fill", "color")),
      $(go.TextBlock,
        { margin: 3 },  // some room around the text
        // TextBlock.text is bound to Node.data.key
        new go.Binding("text", "key"))
    );

  // create the model data that will be represented by Nodes and Links
  var nodeDataArray = [
    { key: "Alpha", color: "lightblue" },
    { key: "Beta", color: "orange" },
    { key: "Gamma", color: "lightgreen" },
    { key: "Delta", color: "pink" }
  ];
  var linkDataArray = [
    { from: "Alpha", to: "Beta" },
    { from: "Alpha", to: "Gamma" },
    { from: "Beta", to: "Beta" },
    { from: "Gamma", to: "Delta" },
    { from: "Delta", to: "Alpha" }
  ];
  diagram.model = new go.GraphLinksModel(nodeDataArray, linkDataArray);
  window.myDiagram = diagram;

 window.goCode2 = function(pre) {
  if (diagramclass === undefined) diagramclass = go.Diagram;
  if (typeof pre === "string") pre = document.getElementById(pre);
  var f = eval("(function () {window.img = " + pre.textContent + "})");
  f();
  pre.parentElement.insertBefore(img, pre.nextSibling)
}

 window.goCode3 = function(pre) {
  if (diagramclass === undefined) diagramclass = go.Diagram;
  if (typeof pre === "string") pre = document.getElementById(pre);
  var f = eval("(function () {" + pre.textContent + "})");
  f();
}

  window.addSVG = function(img) {
    obj = document.getElementById("severalImages");
    img.className = "images";
    obj.appendChild(img)
  }
</pre>
<script>goCode("diag", 300, 150)</script>

<hr/>
<p>
Calling makeSvg with no arguments or with an empty properties object results in a scene that is the same size as the Diagram's viewport.
</p>
<pre class="lang-js" id="code0">
myDiagram.makeSvg();
</pre>
<script>goCode2("code0");</script>

<hr/>
<p>
Calling makeSvg with an object that has the "scale" property set to 1 results in a scene that includes the whole diagram,
not just the area visible in the viewport.  However, the empty areas around the document bounds are trimmed away.
</p>
<pre class="lang-js" id="codeA">
myDiagram.makeSvg({
  scale: 1
});
</pre>
<script>goCode2("codeA");</script>

<hr/>
<p>
Setting the scale property will create a scaled SVG Scene that is precisely large enough to contain the Diagram. The following SVG is created with a scale of 2.
</p>
<pre class="lang-js" id="code1">
myDiagram.makeSvg({
  scale: 2
});
</pre>
<script>goCode2("code1");</script>

<p>
  <em>Note how, unlike an image, you can select the text.</em>
</p>

<hr/>

<p>
The following SVG is created by setting the size option of makeSvg. Note that the canvas is scaled uniformly and any extra space is placed on the bottom or right side of the SVG.
</p>
<pre class="lang-js" id="code2">
myDiagram.makeSvg({
  size: new go.Size(100,100)
});
</pre>
<script>goCode2("code2");</script>

<hr/>

<p>The following SVG is also created by setting the size option of makeSvg, but only the width is set. The height will be whatever size is needed to uniformly contain the Diagram.</p>
<pre class="lang-js" id="code3">
myDiagram.makeSvg({
  size: new go.Size(100,NaN)
});
</pre>
<script>goCode2("code3");</script>

<hr/>

<p>The parts option allows us to specify an <a>Iterable</a> collection of Parts to draw. This is useful if you only want to make an image of part of the diagram, such as a selection of nodes.</p>
<pre class="lang-js" id="code4a">
  myPartsList = new go.List();
  myPartsList.add(myDiagram.findNodeForKey("Beta"));
  myPartsList.add(myDiagram.findNodeForKey("Delta"));
</pre>
<script>goCode3("code4a");</script>
<pre class="lang-js" id="code4">
myDiagram.makeSvg({
  parts: myPartsList
});
</pre>
<script>goCode2("code4");</script>
<p>Or drawing only the links:</p>
<pre class="lang-js" id="code4-2">
myDiagram.makeSvg({
  parts: myDiagram.links
});
</pre>
<script>goCode2("code4-2");</script>

<hr/>

<p>Setting both scale and size creates an image that is scaled specifically and cropped to the given size, as in the following image.</p>
<pre class="lang-js" id="code5">
myDiagram.makeSvg({
  scale: 1.5,
  size: new go.Size(100,100)
});
</pre>
<script>goCode2("code5");</script>

<hr/>

<p>We may want a very large, scaled image that has a limit on its size, and we can use the maxSize property to constrain one or both dimensions. The following image has a very large scale applied but is limited in size horizontally, so some horizontal cropping will occur.</p>
<p>The default value for maxSize is <code>go.Size(2000, 2000)</code>, and specifying <code>go.Size(600, NaN)</code> is equivalent to specifying <code>go.Size(600, 2000)</code>. If we wanted no cropping on the height we could instead write <code>go.Size(600, Infinity)</code>.</p>
<pre class="lang-js" id="code6">
myDiagram.makeSvg({
  scale: 9,
  maxSize: new go.Size(600, NaN)
});
</pre>
<script>goCode2("code6");</script>

<hr/>

<p>Setting both position and size creates a diagram image that is positioned specifically and cropped to the given size. When a position is set but no scale is set, the scale defaults to 1.</p>
<pre class="lang-js" id="code7">
myDiagram.makeSvg({
  position: new go.Point(20,20),
  size: new go.Size(50,50)
});
</pre>
<script>goCode2("code7");</script>

<p>Setting the background to a CSS color string will replace the transparent Diagram background with the given color.</p>
<pre class="lang-js" id="code8">
myDiagram.makeSvg({
  size: new go.Size(NaN,250),
  background: "rgba(0, 255, 0, 0.5)" // semi-transparent green background
});
</pre>
<script>goCode2("code8");</script>

<hr/>

<p>In the following code we use the document bounds to split the Diagram into four equal parts, making four images out of each part. In this way we can prepare images for pagination, making a gallery, or printing purposes. The four images created are shown below.</p>
<pre class="lang-js" id="manyImgCode">
    var d = myDiagram.documentBounds;
    var halfWidth = d.width / 2;
    var halfHeight = d.height / 2;
    svg = myDiagram.makeSvg({
            position: new go.Point(d.x, d.y),
            size: new go.Size(halfWidth,halfHeight)
          });
    addSVG(svg); // Adds the SVG to a DIV below

    svg = myDiagram.makeSvg({
            position: new go.Point(d.x + halfWidth, d.y),
            size: new go.Size(halfWidth,halfHeight)
          });
    addSVG(svg);

    svg = myDiagram.makeSvg({
            position: new go.Point(d.x, d.y+ halfHeight),
            size: new go.Size(halfWidth,halfHeight)
          });
    addSVG(svg);

    svg = myDiagram.makeSvg({
            position: new go.Point(d.x + halfWidth, d.y + halfHeight),
            size: new go.Size(halfWidth,halfHeight)
          });
    addSVG(svg);
</pre>
<div id="severalImages"></div>
<script>goCode3("manyImgCode");</script>

<hr />

<p>
  You can open the SVG in a new window by appending it to the DOM of a new page:
</p>

<button id="openSVG">Open SVG</button>

<pre class="lang-js" id="codea1">
var button = document.getElementById('openSVG');
button.addEventListener('click', function() {
  var newWindow = window.open("","newWindow");
  if (!newWindow) return;
  var newDocument = newWindow.document;
  var svg = myDiagram.makeSvg({
    document: newDocument,  // create SVG DOM in new document context
    scale: 9,
    maxSize: new go.Size(600, NaN)
  });
  newDocument.body.appendChild(svg);
}, false);
</pre>
<script>goCode("codea1");</script>

<hr/>

<h2 id="DownloadingSVGFiles">Downloading SVG Files</h2>
<p>
You do not need to involve the web server if you want the user to download an SVG file.
See the sample <a href="../samples/minimalSvg.html" target="_blank">Minimal SVG</a>.
Note that that sample only downloads a single SVG file, but that file can cover the whole document.
</p>

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